1. Field of the Invention
The present invention relates to an ink delivery system for a liquid electrophotographic color printer, and more particularly, to an ink delivery system for a liquid electrophotographic color printer having a structure capable of recycling a liquid carrier separated from ink supplied through an ink supplier.
2. Description of the Related Art
In general, in an electrophotographic printer, a latent electrostatic image corresponding to various colors is formed on a photosensitive medium such as a photoreceptor belt by irradiating laser beams onto the photosensitive medium by a laser scanning unit (LSU), and then the latent electrostatic image is developed by supplying a developer liquid containing a toner mixed with a carrier, for the image to then be transferred to a sheet of print paper.
As shown in FIG. 1, a conventional development apparatus includes a plurality of laser scanning units (LSUs) for forming a color image corresponding to a latent electrostatic image on a photoreceptor belt 10, a drying/condensing unit 30 for drying/condensing a carrier remaining on the photoreceptor belt 10 after development, and an ink delivery system for supplying a developer liquid of a predetermined concentration and volume suitable for development and recovering a carrier condensed and dried by the drying/condensing unit 30 after being used in development.
The developer liquid is ink of a concentration of about 2-4 wt % obtained by mixing concentrated ink containing about 9 wt % powdered toner supplied from an ink cartridge 41 and a liquid carrier supplied from a carrier cartridge 43. The toner includes pigments indicating different colors, i.e., yellow (Y), magenta (M), cyan (C) and black (K) colors.
The ink delivery system includes a plurality of ink cartridges 41 in which concentrated ink corresponding to different colors is stored, a carrier cartridge 43 in which a carrier is stored, a plurality of circulation tanks 44 in which developer liquid of corresponding different colors is stored, and a plurality of jet portions 47 for jetting the developer liquid to development gaps G between development rollers 21 of the plurality of development units 20 and the photoreceptor belt 10 positioned corresponding thereto. The ink cartridge 41 includes an agitator 42, by which the concentrated ink accommodated therein is not precipitated, and is disposable and can be replaced when the concentrated ink is used up. Also, the carrier cartridge 43 is disposable and can be replaced when the carrier contained therein is used up.
The respective circulation tanks 44 are installed under the corresponding development units 20, and supply developer liquid through the jet portions 47 and receive the residual developer liquid after being used for development so that the developer liquid is continuously supplied to the development gap G during development. A concentration sensor 45 for sensing the concentration of the developer liquid contained in each of the circulation tanks 44 is installed in each of the circulation tanks 44. Also, an upper limit level sensor 46a and a lower limit level sensor 46b for sensing the amount of the developer liquid contained in the circulation tank 44 are installed in the upper and lower portions of each of the circulation tanks 44.
Each of the jet portions 47 includes a jet path 47a through which the developer liquid is supplied, a jet pump 47b installed in the jet path 47a for pumping the developer liquid, and a nozzle 47c installed at an end of near the development gap G for jetting the developer liquid to the development gap G.
The waste ink contained in the respective circulation tank 44 is exhausted to a waste ink disposal tank 49 via an exhaust path 48.
The drying/condensing unit 30 includes a drying roller 31 for absorbing the carrier remaining on the photoreceptor belt 10, regeneration rollers 33 for regenerating the absorbed liquid carrier into a vapor carrier by heating the drying roller 31 while rotating in contact with the drying roller 31, a condenser 35 for condensing the vapor carrier, and a condensation tank 37 for storing the carrier condensed by the condenser 35.
The carrier stored in the condensation tank 37 is supplied to the carrier cartridge 43 via a pump 39.
The amount of the concentrated ink and the carrier supplied from the ink cartridge 41 and the carrier cartridge 43 is determined by the concentration and volume of the developer liquid contained in the circulation tanks 44, sensed by the concentration sensor 45 and/or upper and lower limit level sensors 46a and 46b.
As described above, in the conventional ink delivery system for a liquid electrophotographic color printer, when the carrier is used up, the overall cartridge must be replaced.
Thus, to supply the carrier exclusively used for a liquid electrophotographic printer, a user must buy a carrier cartridge as well as an ink cartridge for replacement, which is costly and burdensome.
Also, when the concentrated ink is used up, the entire ink cartridge must be replaced. At this time, functional parts such as an agitator included in the ink cartridge must be altogether replaced, which as a whole, raises the cost of the ink cartridge.